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Double parth extrution

Double parth extrution

Double parth extrution

(OP)
Hey guys. Im trying to draw something that i think requires the extrution to follow multiple paths, and i do not know of a way to make my AutoCAD 14 do that. I am trying to draw a wing that has a shape of a half ellipse (Ellipse with a flat bottom) that needs to be extruded at an angle and also get narrower on the inside part of the angle as it extrudes. I cannot think of a way to do this without the ability to make the extrution follow multiple (4) paths.

Think of how a wing is shaped on a 50's jet fighter like a Mig 15. The wing starts out the the body. Its rounded on the top side and flat on the bottom to generate lift. Its angled at like 45 degrees towards the back and it gets narrower as it gets farther from the airplne's body. How would you draw that in true 3d with can 14?

Tyson

RE: Double parth extrution

Probably way beyond AutoCADs ability, hope you get a solution.

RE: Double parth extrution

I've work with Autocad's 3d solid, and I can tell you that there is no way you can draw the wing you wanted with autoCAD solid modelling.

the only way you can do is using the surface modelling.  I suggest using edgesurf and using multiple surface to achieve the wing model.  For your refference, the model will be hollow, not solid.

RE: Double parth extrution

hey never say never you just have to sometimes change your thinking to get what you want try using 2 eliptical cones and a couple of eliptical shaped cylinders and som wedges
and use addition and subtraction and you can get very close to what you want just depending on how long you want to spend on it belevie me some one told me that drawing thread like objects in autocad 2000 was impossible and it only took me 2 to 3 weeks to do it

RE: Double parth extrution

(OP)
My CAD instructor used to go on about how AutoCad is the program that Boeing uses to design airplanes. If the darn thing cannot draw an accurate wing, what good is it?

RE: Double parth extrution

I use acad to make wing sections all the time, (I work for a jet engine supplier.)  This is how I do it, but bear in mind I don't use Acad for 3D work, cos I don't think it's very good at it! You'll have to create a series of sections of your wing, each in 2D, but at the appropirate z height. What I then do is loft a surface or a solid through the sections I have created. I've got a sneaking suspician that you can't loft in Acad, so my suggestion would be go download the demo version of Rhino 3D, (find it with a search engine), and loft your sections using that. Then export it back into Acad.  Email me if you get stuck jbowen@tcd.centrax.co.uk, and I'll try to help.

RE: Double parth extrution

It is relatively easy to surface model a wing as you have described.  As Knobhead has stated, you need to draw the various stations (sections) of your wing in the proper 3D orientation.  Then using the EDGESURF command, create a surface between each of the wing stations.  You will probably need to step up the values of SURFTAB1 and SURFTAB2 variable considerably above the defaults to get any type of quality surface model.

I don't think ACAD can create a solid model of the wing, just a surface model.  

As far as Ahraxx's post, I think his instructor is mistaken.  Boeing uses Catia (commercial business) and Unigraphics (military, former McDonnel Douglas business).

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